Mechanical hammer



April 22, 1930.

A. PFLUGERET AL MECHANICAL HAMMER Filed Sept 24, 1927 2 Sheets-Sheet l Mad April 22, 1930. A. PFLUGER ET AL ME CHANI CAL HAMMER Filed Sept. 24, 1927 2 Sheets-Sheet 2 Ma d% i I Jnwenlaz' Via ra/ 2???? Patented Apr; 22, 1930 mm rrnnena; xon'nan rinses, or fnssnnienir o i A noafion'mea septcinher 2'4,- 19a7,; smart. 221,723,] and iaieq iii my 15; ggef M 1 1 Our invention relates to mechanical percussive' tools, for instance, to hand rammers, and

more particularly totools,', in which an 'internal combustion-engineis provided ,for op p l trate'd diagrammatically 5 crating-the tool It is an object of Ourinvention provide atoolin which the energy imparted to the tool is partly utilizedfor supplying the cyl x ind'er jofthe engine with a fresh charge of combustible mixture.

To thisend we? so. determine the length 7 ofa part of the engine, forinstance its piston rod, with respect to: thetotallengthof the en ine, for instanceits' c 'linder,.tha't-the' di erence-in the lengths 0 the; two parts is equalto thesuction stroke of, the, en ine. In'

the caseof a hand-rammer the total ength of the piston and its rod is made less than'the' total length of the cylinder plus the trip, foranamountequal to the suction'stroke so that, withthe rammer, in-its initialipos'ltlon, 1n.

which the tup and the lower end of the pis- I ton rod are resting on the pavement, the'cylin' th'atofigur e; y

inder headi'saboverthe piston fora distance equal to the suction stroke.

, Itis another object of our invention to prb vide means forcontrollin thejo eration of the inlet valve and thei ltion o the engine. simultaneously, and to t isI-end wepr'ovide an' operating lever for the inlet valve which is.

the inlet valve. I

It is still another-object of our invention to provide means for drawing the charge of mixture intoithe engine cylinder beforejstarting' the operation of the tool and'tothis end we; equip'a'piston of theengine, or its rod, with a 40 handle, or handles, for reciprocating the pistial position;

. It is still another abject of ourin 've'ntion, it:

provide means for automatically controlling the inlet" valve'of the engine nic nformity n ,n a n with the pressure in its cylinder, andgto this .end wep'rovide a clutchin connection with mg; a comparatively simple valve oper ti mechanism; 7

head and the elaborate valve the same plane as -Fig. 5;

connected with contacts or other-suitable means for effecting the ignition upon closing .tachable means, if desired, is the cylinder 'curedc to -the-i .piston rod, and 8 are springs V secured to-"the'brackets atone endand'to'the- =j handlesat theother. The extension'ofthe cylinder 1' to which the tup is secured'or with ton in the cylinder when the tool-is in its ini-'- Iopened when the pressurein the cylinder I ceeds .a given'ilimitsl Elna theraccompanying :drajwings, contrivances embodying our invention "are illus-v,

v byway of example. Inth'e drawing"s:*..- Figs. 1 to 5 illustrate a: contrivance -h'av-"- Figszfi t0-8 illustrate the cylinderhead of a contrivance'having a more; elaborate valve" nd} elongitudinalsections I showlng e;contriv'ance in various stages of itsoperat ibn; p f vi n 05 F g. 5. s anaxial'section of the cylinder head of this contri'van'ce', drawn to alarger sc'alef 1 my v Fig. 6- is' an axial section ofthe cylinder gear, taken in Fig..7j 1s an axial section taken ht anglesito FigJG and viewed fromthe eft .F' s. is aplanjview of thec linder'head, u artl :in sect on on the line-V II.'VIII in ig. ,and'drawnto'a smallerscale.

Referring now to the drawings-and first to F1gs. 1 to 5, these illustrate a pavement ram" but it is understood that our contrivance may to he used for'anywother-operation.

1- is the cylinderof'a'n internal combustion eng1ne,2 1s a tap which; is shown integral with thecylinder but might be securedtoit by dehead, '4-are handles secured to or formed in- I tegral with ,;th'e cylinder head,-5fis a piston inthe-cylinderi 1'; 'Gis-it -Pi'ston rod 'which is free to slide the tup 2, P 7, are brackets sewhich'fit is integral, asshown,'is slotted for the brackets 7,:7. I 05 -Referring now' to' Fi" 5,; 10 is a control lever fori the valve 'mecEanismwhich is ful- 'crumed to an extension'bf the cylinder head 3 at9, and 11 is acoi'ledj s ring which is secured to'thfe cylinder' head: orto one ofits a ad - the cylinderwith the pp han les 4, as shown, and tends to return the leve to its initial position after it has been depressed. 12 is a cam projecting inwardly from the fulcrum 9 and enga ing .aslot in the hollow stem 13 of a com ined exhaust and inlet valve 14,15is a choke tube inserted in the upper end of the extension, 16 is a jet through which fuel is supplied to the bore 17 of the choke tube from any carburetor or .su'pply, not shown, 18 is a secondary-airpassage in the base of the headextension, 19are passages in the hollow vstem 13 for allowing the secondary air to enter the cylinder past the valve 14 when it isopen, and 20 are exhaust slots in the cylinder which are adapted to be uncovered by. the piston .Thestem13. of

the valve 14 is slotted for thejet 16 so that its movement-is not interfered with; is a contact on the lever 10, 4' is a corresponding contact on the handle .4, and 4" is a cable connecting the contacts 4" with a. sparking plug as shown at 45 in Fig. 6. I

Assuming that-the rammer. is in its" initial position as shown in Fig. 1," in which, as explained inthe introduction, the clearance etween the piston 5 and the cylinder head is equalto thesuction stroke,--theinlet valve 14 is lifted by the spring 11 throughthe medium of the lever 10 and thefcam'12, the piston 5 is raised by handthrough the medium of the brackets 7, and returned to'its initial position, drawing a fresh charge; into the cylinder;

When the-control lever 10 is rdepressedther valve 14 which had been held open by: the spring 11, is seated. The space above the pisten 5 is filled with an explosive mixture and is ignited by automatic means connected with the control lever.. 'Such means are not shown in these. figures but will vbe described with reference .to Figs. 6 to-8. The contrivz anceis in the position illustrated in Fig. '1,

with thetup 2 andthe 'piston rod 6 restingon the pavement or the like. Whenthemixture is ignited, the chargeexpands and-raises I against the tension cf the springs'S, 8.; attained the position in Figsv 2, the :exhaust slots 20. are uncovered but the expanding vases still act on the cylinder so-that it is fura flierraised into the position illustrated in Fig. 3 in which the brackets .7 of thesprings. 8 prevent further upward movement. of the cylinder with respect to. the piston5. The

momentum of the cylinderand tup'will now lift the contrivance away. from thesurface on which it is supportedbyits pistonrod, and it will jump into the position illustrated in Fig. 4. In the meantime the gases abovethe piston have been completely expanded, and for the most artdischargedthrough thevex haust slots. and pull the piston 51:0 theend ofits stroke, the residue ofg ases which is intercepted in front of the piston after it has moved past the exhaust slots being. discharged past the en the cylinder has he springs 8 will now contract valve 14 which has been moved away from its seat by the spring 11.

When the parts have losttheir momentum they will return to the initial position as shownin Fig. land while the piston 5 is moving away from thecylinder head itwill draw afresh charge into the cylinder which is ignited as described bydepressing the lever 10..

It'wi'll be understood that'in this contrivanceit is necessary to release the control lefiver immediately after it has been operated so thatthe spring ll is free to open the valve 14at the right time. In the valve gear illustrated in'Figss6, 7 and8, means are provided in connection with the' control lever for automatically disconnectin' it from the :valve so that the lever can-beepre'sscd' for any length of time without interfering withthe operation of the valve. 1

Referring now to Figs. cal'pa-rts as the cylindery1,its head 3, the

handles 4, etc:, have been designated by the same reference numerals as in Figs..- 1 t0 5'.

.Fig.- 6 shows the control lever 10 partly depressed. Its end is-curvedso asto extend in-parallel with one of: the handles and to be able. to enter a recess in the upper face of the handle. 24 is a cam which is free to turn on the fulcrum. 9 of the lever 10 and is; adapted to engage the valve spindle 27 with its forked end 26. is an abutment on the cam 24 and this. abutment is adapted to be' engaged by a :latch 22., The latch 22is adaptedto turn about a" pin 21 in the lever 10, and a spring 23 on the lever tends to hold the latch 22 engaged, withtheabutment- 25 so that the :lever- 10 and the. cam 24 are positively engaged.

28 is a collar which is engaged from below by the fork-shaped endof the cam 24, 30

6, 7, and"8, identi- 1 is a spring inserted "between the' moveable collar-{28. and a collar '29 on the.end of the valve sp1ndle'27, and endowed with-some ini-' ;tial pressure. ..-42 is a spring whichis weaker than thespring; 30 and is inserted between the top surfaceof the collar 29 and a cap 31 which is screwed on the guide 38 of the valve stem.

33 are'chambers formed in the cylinder -head3 on either side, 32 are pipesconnected with the carbureter, not shown, at oneend and withthe chambers 33at theother, 34

are passages connecting thechambers 33 vwith'chtnnbers'35, one on each side or the guide'38 which is extended into a wall projecting'on either side of thespindle 27, as will appear' fromFig. 8. 36 are p'erfo'ra limited to the exact of its piston der head 3, 44 are its electrodes, and. 43 is its contact. The contact is connected with the sparking plug by wires, not shown, and adapted to be closed by the cam 24 after the control lever 10 has performed a given stroke.

46 is a bore in the cylinder head, .47 is a piston; adapted to slide in a cylinder on the cylinder head against the act-ion of a s ring 48, and 49 is the rod of the piston whicii rod is adapted to engage a rearward extension of the latch 22. t

It is not necessary that the pipes 32 and the chambers to which they are connected should be duplicated as illustrated by way of example. I 1 The operation of the valve gears is as folows:

In the position illustrated in Fig. .6 the lever 10 has been depressed until the valve 40 has been closed, compressing thespring 42 while no substantial tension is exerted in the stronger spring 30. Upon further depression of the lever, a certain pressure will also be exerted on the stronger spring 30 and, at thesame time the contact 43 will be closed by the cam 24 so that a spark will be gen-' erated at the electrodes 44 the sparking plug and the mixture in the cylinder will'be' ignited. The pressure of the expanding mixture is transmitted to the piston 47 which will rise in its cylinder and through the medium I rod 49, disconnect the latch 22 from the cam 24 so that the camis free to turn on the fulcrum 9 independently of the lever 10 and the valve 40 is lifted fromits lslezat by the joint action of the springs 30 and When the. valve 40 has been opened and the piston is expelling the exhaust gases from the cylinder they will be discharged through'the passages 40, lifting thespring plate 41. When the suction vperiod begins the valve 41 closes automatically and the valve 37 opens so that mixture is drawn into the cylinder from the passages or ports 36. Automatic means might be provided for operating the valve 14 but it has been found preferable to control the contrivance by hand. ,v

Other means than those shown and described may be provided for supplying mixture to thecylinder. In general, we wish it.

to be understood that we do not desire tn be person skilled in the art.

bustible mixture to said cylinder, and means fforigniting the mixture, "cylinder,measured'from, its inner end to fromits inner end to the striking details ofconstruction shown and described for obvious modificathe length of said the striking face of said't'upiand the length of said piston and piston'rod, measured from the inner face of said piston .tothe end of said rod, being sodetermined that their differen'ce is, equal, to] the. suction stroke of said pistom I 2. A mechanical percussive tool comprising a cylinder, a tup on the lower end of said cylinder, a piston rod connected with said piston-,. means for supplying combustible mixture to said cylinder, and means for igniting the mixture in said cylinder, the:

measured from its length of said cylinder, inner end to the striking face of said tup, and the length of said piston and piston rod, measured from the inner face of said piston to the end of said rod, being so determined that their difference is equal to the suction stroke of said piston. 1

' 3. A mechanical'percussive tool comprising a cylinder, a tup on said cylinder, a pis ton in said cylinder, a piston rod connected with said piston, an inlet valve on said cyl inder, means for supplying combustible mixture to said inlet valve, means for igniting the mixture, and a handle for oper ating said valve and said igniting means in unison, the length of said cylinder, measured face of said tup, and the. length of said piston and piston rod, measured from the inner face of said piston to the end of said rod, bein so determined that their difference is equfi tn the suction stroke of said piston.

4. A mechanical percussive tool comprising a cylinder, a tup on said cylinder, a piston in. said cylinder,,a piston rod connected with said piston, means for supplying com" bustible mixture to said cylinder, means for igniting the mixture, the'length of said cylinder, measured from its inner end to the striking face of said tup, and the length of said piston and piston rod, measured from the inner face of said piston to the end of said rod, being so determined thattheir difference is equal to the suction stroke of said piston, and means extending through said cylinder-and operatively connected with said piston for moving said piston andsaid cyl" inder byzhand-l' V 5 5. A mecha c'al percussivetool compris ing a cylinder, a; tup on said cylinder, a piston in said cyl'infd'en', a'pisto'nrot connected with said piston *an inlet valve inder, means 'o r supplying c'o nibustible mixture to said inlet valve, means for igniting the mixture, a handle for operating said valve and said igniting means in unison, a clutch intermediate said handle and said ice valve, automatic means for holding said said cylinder, measured from its inner end to the striking face of said tup, and the length of said piston and piston rod, measured from the inner face of said piston to the end of said rod, being so determined that their difference is equal to the suction stroke of said piston. e v

In testimony whereof. we aflix our signatures.

um i ,7 AhBERTPFLflGERe KONRAD HAAGE; 

